What happens to the deaerator (DA) when returning condensate is hotter than expected?

When returning condensate to the deaerator is hotter than expected, the steam bypass closing and the vacuum breaker opening is a critical response to maintain proper operations within the system. The deaerator is designed to remove dissolved gases from the condensate by using steam to heat the water, thereby enhancing the efficiency of the system. If the returning condensate is at a higher temperature than the design specification, it indicates that the system may not be operating optimally or that there could be an issue with the heat exchange process.

In this scenario, the closing of the steam bypass helps to ensure that excess steam is not introduced into the deaerator, which could lead to increased pressure or unnecessary heat input, possibly causing the water to overheat. Simultaneously, the opening of the vacuum breaker allows for pressure relief within the system, ensuring that any excess pressure created by the hotter condensate can escape. This helps to maintain the operational integrity of the deaerator and prevent potential safety issues.

By effectively managing the steam flow and pressure through the deaerator, the system can continue to operate efficiently, ensuring optimal removal of gases from the water and maintaining overall performance.